collector's item vs showpiece

collector's item and showpiece both are nouns.

Word	Noun	Adjective	Verb	Adverb
collector's item	Yes	No	No	No
showpiece	Yes	No	No	No

As nouns, collector's item and showpiece are synonyms defined as:

collector's item and showpiece: the outstanding item (the prize piece or main exhibit) in a collection

Other synonyms of collector's item include piece de resistance.

collector's item (noun)	showpiece (noun)
the outstanding item (the prize piece or main exhibit) in a collection	the outstanding item (the prize piece or main exhibit) in a collection